For the purpose of preventing the intrusion of rain water and so on, a seal member, which is molded typically from synthetic rubber and is generally called weather strip, is interposed in a gap between a door and a vehicle body. Recently, with the aim of reducing the wind noise and noises from air leakage in addition to improving the sealing effect, weather strips of higher reaction force or, in other words, weather strips having higher elastic coefficients are being preferred. And, this high reaction force tends to prevent a full latching of the door latch upon closing of the door and may cause an only partially closed state of the door. Therefore, it is sometimes necessary to forcibly close the door to overcome the reaction force of the weather strip and to obtain a fully latched state of the door latch. However, when the door is forcibly closed, the sound thereof and the resulting sudden change in the cabin pressure may cause discomfort to the passenger.
To resolve such a problem, it is conceivable to move a striker, by a suitable means, which is mounted to the door to engage with a latch assembly mounted to the door to keep the door closed. Specifically, the striker may be placed at an outwardly position in advance so as to achieve a latching before the reaction force of the weather strip starts acting upon the door and, after the door latch assembly is fully latched to the striker, the striker is positively driven to a position which causes complete deformation of the weather strip for sufficient sealing effect and complete closure of the door.
However, in order to pull in the striker from its latched position against the reaction force of the weather strip, a substantially strong force is necessary and it is difficult to install, in the limited space in the interior of the body panel, a drive means which can drive the striker. It will be even more difficult to install such a drive device in the center pillar of a four-door passenger car.
Furthermore, in view of the fact that a substantially strong force is necessary to fully close the door and to maintain the door closed, the mechanical strength of the striker must be sufficiently high for maximum safety. Therefore, the striker is preferred to be made of high tensile strength steel. As a result, friction and impact sounds may be produced from metallic contacts during the action of the striker and it may give discomfort to the passenger. Furthermore, in order to drive the striker from the interior of the body panel, it is necessary to form an opening in the body panel adjacent to the moving part of the striker and, if it allows intrusion of rain water or dust, the interior of the door panel may be corroded causing ill effect to the drive means and the body panel itself.
Additionally, in designing such a power assisted automotive door, the cost of manufacture must be minimized and fail safe features must be incorporated from practical view points. For instance, if an attempt is made to drive the striker for instance with an electric motor, an electric switch therefor will be necessary and the labor and the cost necessary for manufacture thereof will increase. If a manual switch is installed near an instrument panel, not only the feeling of the vehicle handling may be impaired but also the equipment will be wasted if the user forgets to use it. And the device must work properly even when the user is not aware of its action.